bluewave

2004-2005 was a very warm winter across the US.

94-95 and 04-05 were both warmer Modokis. That’s why they were grouped together. When you get a more -PDO-like Modoki which matches the region north of Hawaii it’s just not as cold as the +PDO counterparts.

I was talking about cold not snow. We can always get snowier winters with warmer patterns with the right storm track. I had better quality snowstorms in my area from 15-16 to 17-18 even though it was much warmer than 13-14 and 14-15.

The more significant SST anomaly pattern that fall was closer to a strong +PDO with very cold SSTs north of Hawaii. It didn’t matter that the SSTs were colder along the West Coast since the pattern further west was driving the bus on the Pacific side. Notice the cold pool and more +PDO-like Aleutian Low.

The 09-10 winter was very different in regard to having the cold pool north of Hawaii. That was associated with the stronger Aleutian low in thst area instead of ridge. So the actual PDO index that winter didn’t match the area north of Hawaii. That’s why I look closely at that area to see if it’s in sync with the PDO. Some years the PDO index is contrary to that region and 09-10 was one of them. So that cold pool north of Hawaii and Aleutian low was actually more like a +PDO. It matched the colder and snowier Modokis in 02-03 and 14-15.

Remember, the whole east based vs west based argument is moot if we get a -PDO. Modoki El Niño’s are warm with a -PDO that has a warm pool north of Hawaii and Aleutians ridge. The sample size is small but the 94-95 and 04-05 Modkis were warm.

5th lowest JUN to SEP -NAO on record.

It’s been a while since the 50/50 low and confluence to our north trended stronger instead of weaker. New run Old run

Our last impressive Arctic shot in October came with the super El Niño in 2015. One of the few times that Newark dropped below freezing during October. Widespread 20s in suburbs. for October 19, 2015 through October 19, 2015 Click column heading to sort ascending, click again to sort descending. State Name Station Type Lowest Min Temperature NY WESTHAMPTON GABRESKI AP WBAN 20 CT MERIDEN MARKHAM MUNICIPAL AP WBAN 21 CT DANBURY MUNICIPAL AP WBAN 21 NY CARMEL 4N COOP 21 NY MONTGOMERY ORANGE COUNTY AP WBAN 22 CT NEW HAVEN TWEED AP WBAN 23 NY SHRUB OAK COOP 23 CT MIDDLETOWN 4 W COOP 23 NY PORT JERVIS COOP 23 CT DANBURY COOP 23 NY YORKTOWN HEIGHTS 1W COOP 23 CT ANSONIA 1 NE COOP 23 CT GROTON NEW LONDON AP WBAN 24 NJ CRANFORD COOP 24 CT SAUGATUCK RESERVOIR COOP 24 CT MOUNT CARMEL COOP 24 CT NORWICH PUBLIC UTILITY PLANT COOP 25 NJ CHARLOTTEBURG RESERVOIR COOP 25 CT STAMFORD 5 N COOP 26 NJ CANOE BROOK COOP 27 NJ CALDWELL ESSEX COUNTY AP WBAN 27 NY WESTCHESTER CO AP WBAN 27 NY UPTON COOP - NWSFO NEW YORK COOP 27 NJ TETERBORO AIRPORT COOP 28 CT GROTON COOP 28 NJ TETERBORO AIRPORT WBAN 28 CT BRIDGEPORT-SUCCESS HILL COOP 28 NY SHIRLEY BROOKHAVEN AIRPORT WBAN 28 NY ISLIP-LI MACARTHUR AP WBAN 29 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 30 NJ NEWARK LIBERTY INTL AP WBAN 31 NY MOLLOY CERCOM COOP 32 NJ HARRISON COOP 32 NY MATTITUCK COOP 32 NY FARMINGDALE REPUBLIC AP WBAN 33 NY BRIDGEHAMPTON COOP 33 NY MOUNT SINAI COOP 34 NY NY CITY CENTRAL PARK WBAN 35 NY CENTERPORT COOP 35 NY BAITING HOLLOW COOP 35 NY JFK INTERNATIONAL AIRPORT WBAN 36 NY MONTAUK AIRPORT WBAN 36 NY LAGUARDIA AIRPORT WBAN 37 NY SETAUKET STRONG COOP 37 NY RIVERHEAD RESEARCH FARM COOP 38 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1936 25 0 2 1969 28 0 3 1976 29 0 - 1975 29 0 - 1937 29 0 4 1997 30 0 - 1965 30 0 - 1948 30 0 - 1940 30 0 5 2015 31 0 - 1988 31 0 - 1974 31 0 - 1972 31 0 - 1966 31 0 - 1952 31 0 - 1944 31 0 - 1933 31 0

We have been the wettest part of the country.

Close to average next 10 with some milder days and cooler ones mixed in. Then maybe moderating a bit week 2. But the means are falling this time of year anyway. The coolest departures look like they will set up over the SE.

Yeah, the rate of Nino 3.4 warming peaked back in August. This coincided with the actual peak in 1+2 and peak in WWB activity so far. While the WWBs have picked up in October relative to September, there is less of a warm water supply in 1+2 to spread out west like we had in August. So Nino 3.4 SSTs continue around 1.43 even with better WWBs this month. The current lack of a strong oceanic kelvin wave and lower upper ocean heat content is slowing things down relative to what we have seen during past El Niño events.

August was our only decent WWB month. So that’s why we had the steep Nino 3.4 rise. The CP trade wind index for August says it all. We can see the decline in WWBs for September leading to the Nino 3.4 drop in recent weeks. https://www.cpc.ncep.noaa.gov/data/indices/cpac850

October 2009 was the last time the CONUS had a top 5 coldest month. https://www.ncei.noaa.gov/access/monitoring/monthly-report/national/200910#:~:text=The average October temperature of,reinforced unseasonably cold air behind Temperature Highlights - October The average October temperature of 50.8°F was 4.0°F below the 20th Century average and ranked as the 3rdcoolest based on preliminary data. For the nation as a whole, it was the third coolest October on record. The month was marked by an active weather pattern that reinforced unseasonably cold air behind a series of cold fronts. Temperatures were below normal in eight of the nation's nine climate regions, and of the nine, five were much below normal. Only the Southeast climate region had near normal temperatures for October.

The one thing that I would add is that this October is running much warmer than years like 2009 and 1976. October 2009 was actually the 4th coldest for the CONUS on record and 1976 2nd coldest. Same way like this summer was much warmer than 2009 even though both years had great summer blocking patterns.

No problem. Not saying I know for sure what is going to happen. Just not a big fan of this persistent -PDO La Niña background state .I don’t mind it as much when it’s uncoupled like Jan 22 and Dec 20 to Jan 21. But it’s very tricky to try and figure out ahead of time when it’s going to couple or not. Plus we have these interference patterns which can arise when the ENSO and PDO our out of phase. Also these troughs seem to find a way to sneak in out West during recent years.

The relevant part is how even a weak -PDO with an El Nino can put a trough in the West like 72-73.

The issue with WWBs coming on so late is that any oceanic kelvin wave generated would also be too late to move the El Niño much more past what we have already seen. Most fall oceanic kelvin waves that have sharp El Niño warming get generated by WWBs during late summer into September. This year we had stronger trades and an absence of WWBs. So any potential kelvin wave warming would come after the El Niño has already peaked.

Tug of war between El Niño in the tropics and -PDO in subtropics or extratropical regions.

It doesn’t have to if the -PDO is coupled well. We can remember back in the 18-19 El Niño that struggled to couple how the well coupled -0.42 -PDO was enough to place the trough in the West. But each winter is different so we’ll just have to see how things play out. Plenty of variables and combinations to factor in.

MJO 7 region forcing west of the Dateline like we are currently getting can mimic a MJO 5 when the PDO is very negative.

Hopefully, the MJO 4-6 doesn’t rebound as much as we saw with the last record +IOD back in 19-20. That event only suppressed convection near the Maritime Continent into early December. So IODs are mainly a fall event and the influence wanes by the winter. Once the IOD dropped under +1 in December 2019, the Maritime continent convection returned.

OCT…….6-8…..0.49

The only real winters in the 90s were 93-94 and 95-96.

Crazy how Sandy was exactly a year later.